Which of these is a typical property of a substance that is composed of atoms that are held together by covalent bonds?
a. it conducts electricity when in solid form. b. it conducts electricity when in molten form. c. it conducts electricity when it is dissolved in water. d. it does not conduct electricity in any form.

Consider the following reactions. (note: (s) = solid, (l) = liquid, and (g) = gas.) mg(s) + ½o2(g) → mgo(s) + 146 kcal/mole h2(g) + ½o2(g) → h2o(g), δh = -57.82 kcal/mole what type of reaction is represented by the previous two examples?

Astudent is trying to create a table that compares hypotheses, theories, and laws. hypothesis theory law do scientific researchers formulate it? yes yes yes does it explain why things happen? yes yes no yes yes yes is it used to make predictions? no yes yes which of the following questions would most likely fill the blank in the table? is it an intelligent guess? is it newly formulated? is it based on observations? has it been proved?

Which change to the system wood cause the freely-moving piston to lower?